Hydrostatics Lesson 6 © nitatravels

Fluids are Everywhere  Liquids or Gasses  Air is a fluid!!!  Typically take the shape of their container

Fluids: Important Terms Compressible Fluid: Gasses  Take shape of container  Expand to fill container  Can increase its volume Incompressible Fluid: Water  Never expands to fit container  Volume never changes

Hydrostatics   The study of how a fluid behaves at rest.

Hydrostatics- Important Terms   Density Mass of a fluid divided by the volume it occupies.  Which fluid do you think has a higher density at the same temperature? OIL

Hydrostatics- Important Terms   Specific Weight Weight of a fluid per unit volume Found by multiplying density of fluid by the acceleration due to gravity Specific Weight = Density x Gravity

Hydrostatics- Important Terms   Hydrostatic Pressure Static pressure exerted by a liquid Occurs when the fluid is not moving and no object in the fluid is moving Increases at deeper depths Hydrostatic Pressure = Specific Weight x Depth

Finding the Pressure Underwater   Calculated by multiplying difference in elevation in the liquid times the unit weight of the liquid Difference in Pressure = pressure 2 – pressure 1 = unit weight x (depth 2- depth 1)

Hydrostatic Force   Force that liquid exerts on body either fully or partially in the liquid or adjacent to liquid   Formal: the hydrostatic pressure multiplied by the area on which the pressure is acting Hydrostatic Force = Specific Weight x Depth x Area

Buoyancy   Force exerted upward on a body that is fully or partially submerged in a liquid   Discovered by Archimedes in 212BC Archimedes Principle “Any object, wholly or partially immersed in a fluid, is buoyed up by a force equal to the weight of the fluid displaced by the object.”

Buoyancy   Center of buoyancy is the center of gravity of the displaced liquid   How do you stop a submerged object from overturning?   Ho do you keep a floating object from not flipping over? When the center of gravity of the object is directly below the center of buoyancy of the object.   Instability of objects occur when? The center of gravity moves out of vertical alignment with center of buoyancy. Buoyant Force = Weight of the Fluid Displaced by the Object © voithite